莲心碱对大鼠心室肌细胞I_(Na)、I_(Ca-L)及稳态外向K^+电流的影响

采用膜片钳技术，研究了莲心碱（Liensinine，Lien）对大鼠心室肌细胞动作电位及钠电流（INa）、L-型钙电流（ICa－L）及稳态外向K＋电流的影响，Lien30μmol／L可显著地降低动作电位幅度、静息膜电位，延长动作电位时程。Lien10，30μmol／L分别使INa及ICa－L从给药前的（7．9±2．2）nA和（699±175）pA降至（4．3±1．7）、（1．8±1．6）nA和（203±132）、（147±121）pA。Lien10μmol／L还抑制INa、稳态外向K＋电流和ICa－L的I－V曲线并使后者的峰值电流电位略右移。提示Lien有钠、L型钙通道阻滞作用并抑制稳态外向K＋电流，这些可解释Lien广泛的抗心律失常作用机制。

硝苯地平阻断豚鼠心室肌细胞L型钙流特性的研究

选择性L型钙通道阻断剂硝苯地平 (Nif)为常用的工具药 ,因此必须了解它对L型钙流 (ICa(L) )浓度、状态依赖性阻断 ,使用和非使用依赖性阻断等特性。以豚鼠分离的单个心室肌细胞为对象 ,采用膜片钳全细胞记录技术 ,给予 35℃的各种含药物细胞外液快速灌流 ,记录ICa(L) 。结果 :①保持电位 - 80mV ,使用含铯离子的细胞内、外液 ,在 +10mV的钳制电压 ,Nif抑制ICa(L) 的IC50 为 0 .3μmol·L-1;当保持电位为 - 40mV时 ,IC50 为 0 .0 5 μmol·L-1,显示Nif优先选择与失活态钙通道结合。②使用富含钾离子的细胞内、外液 ,对ICa(L) 的非使用依赖性阻断 ,随Nif使用浓度 (30～ 10 0 μmol·L-1)的增加和药物作用时间的延长而加强 ,同时对ICa(L) 的使用依赖性阻断则减小。③在 10s的静息间隔药物作用时间后的第一个实验刺激 ,Nif 3μmol·L-1或 30 μmol·L-1加速ICa(L) 的失活 ,提示Nif对ICa(L) 可能存在激活态阻断。结论 :在生理条件下 ,Nif对ICa(L) 的阻断呈浓度、状态依赖性 ,对ICa(L) 的非使用依赖性阻断随使用浓度的增加和作用时间的延长而加强 ,对ICa(L) 的使用依赖性阻断则随之减弱。

NMDA受体NR2B亚单位特异性单克隆抗体的制备及人胚脑皮层NR2B蛋白表达的研究

目的：制备NMDA受体NR2B亚单位特异性单克隆抗体，并对人胚脑皮层NR2B的表达作免疫印迹分析。方法：制备NR2BC末端934～1457氨基酸与GST的融合蛋白，并以此作为免疫原，经常规杂交瘤技术制备单克隆抗体。用该抗体对不同周龄的人胚脑皮层的NR2B蛋白作免疫印迹分析。结果：本研究制备的NR2B单克隆抗体能特异地识别180kDa的NR2B蛋白，并首次发现人胚脑皮层NR2B亚单位蛋白的表达。结论：成功制备了NR2B特异的单克隆抗体；12周龄的人胚脑皮层组织已有NR2B的表达，表达量随胎龄增大而增高。

Inhibition of Fas/FasL mRNA expression and TNF-a release in concanavalin A-induced liver injury in mice by bicyclol

AIM: Bicyclol, 4,4'-dimethoxy-5,6,5',6'-dimethylene-dioxy-2-hydroxymethy1-2'-carbonyl biphenyl, is a new anti-hepatitis drug. The aim of the present study was to investigate the protective effect of bicyclol on concanavalin A (Con A)-induced immunological liver injury in mice and its mechanism. METHODS: Liver injury was induced by injection of Con A via tail vein of mice and assessed biochemically and histologically. Serum transaminase and tumor necrosis factor alpha (TNF-a were determined. Liver lesions were observed by light microscope. Expressions of TNF-a, interferon gamma (IFN-y), Fas and Fas ligand (FasL) mRNA in the livers were measured by RT-PCR. RESULTS: Serum transaminase level and liver lesions in Con A-induced mice were markedly reduced by oral administration of 100, 200 mg/kg of bicyclol. TNF-a level inserum was also reduced by bicyclol. Con A injection in ducedup-regulation of TNF-a, IFN-7, Fas and FasL mRNA expression in liver tissues. Bicyclol significantly down-regulated the expression of IFN-y, Fas and FasL mRNA, but only slightly affected TNF-a mRNA expression in liver tissues. CONCLUSION: Bicyclol protects against Con A-induced liver injury mainly through inhibition of Fas/FasL mRNA expression in liver tissues and TNF-a release in mice.

Effects of nitric oxide on gastric ulceration induced by nicotine and cold-restraint stress

AIM:Stress induces gastric ulceration in human and experimental animals. People tend to smoke more cigarettes when under stress. Nitric oxide (NO) and nicotine have opposing effects on gastric integrity. The present study examined the possible therapeutic benefit of NO in nicotine-treated rats with stress-induced gastric ulceration.METHODS:Rats drank a nicotine solution while control rats drank tap water for 20 days. The alkoloid was then replaced by water with or without supplementation of isosorbide dinitrate (NO donor) for an additional 10 days. Isosorbide dinitrate was given twice shortly before experiments (acute) or three times daily by oral gavages for 10 days after the rats stopped drinking nicotine solution. At the end of experiments,ulcer index, gastric adhesion mucus content and MPO activity were measured and analysed.RESULTS:Nicotine treatment decreased gastric mucus content and intensified stress-induced gastric ulcer. A higher ulcer index persisted even after the rats stopped drinking nicotine solution for 10 days. Acute NO donor showed no benefit on both mucus and ulcer index in nicotine treatment or/and stress condition.Chronic NO donor treatment reversed the worsening action of nicotine in stomach. Stress increased gastric mucosal myeloperoxidase (MPO) activity, which was antagonized by chronic NO treatment. However, nicotine was unlikely to change mucosal MPO activity.CONCLUSION:The intensifying action of nicotine on stressinduced gastric ulceration persists for 10 days after cessation.Nicotine treatment significantly decreases gastric mucus content that can be restored by chronic NO donor treatment.The present study suggests that NO antagonizes the ulcerogenic action of nicotine through a cytoprotective way.

Identification of two distinct transactivation domains in the pluripotency sustaining factor nanog

Nanog is a newly identified homeodomain gene that functions to sustain the pluripotency of embryonic stem cells.However,the molecular mechanism through which nanog regulates stem cell pluripotency remains unknown.Mouse nanog encodes a polypeptide of 305 residues with a divergent homeodomain similar to those in the NK-2 family.The rest ofnanog contains no apparent homology to any known proteins characterized so far.It is hypothesized that nanog encodes a transcription factor that regulates stem cell pluripotency by switching on or off target genes.To test this hypothesis,we constructed fusion proteins between nanog and DNA binding domains of the yeast transcription factor Gal4 and tested the transactivation potentials of these constructs.Our data demonstrate that both regions N- and C- terminal to the homeodomain have transcription activities.Despite the fact that it contains no apparent transactivation motifs,the C-terminal domain is about 7 times as active as the N-terminal one.This unique arrangement of dual transactivators may confer nanog the flexibility and specificity to regulate downstream genes critical for both pluripotency and differentiation of stem cells.

Inactivation of PTEN is associated with increased angiogenesis and VEGF overexpression in gastric cancer

AIM: To investigate the expression of PTEN/MMAC1/TEP1 and vascular endothelial growth factor (VEGF), their roles in biologic behavior and angiogenesis and their association in gastric cancer.METHODS: Immunohistochemical staining was used to evaluate the expression of PTEN, VEGF and microvascular density (MVD) on paraffin-embedded sections in 70 patients with primary gastric cancer and 24 patients with chronic superficial gastritis (CSG). Expression of PTEN, VEGF and MVD were compared with clinicopathological features of gastric cancer. The relationship between expression of PTEN, VEGF and MVD as well as the relationship between PTEN and VEGF expression in caner cells were investigated. RESULTS: PTEN expression significantly decreased (t= 3.98, P<0.01) whereas both VEGF expression and MVD significant increased (t = 4.29 and 4.41, respectively, both P<0.01) in gastric cancer group compared with CSG group. PTEN expression was significantly down-regulated (t=1.95, P<0.05) whereas VEGF expression (t = 2.37, P<0.05) and MVD (t= 3.28, P<0.01) was significantly up-regulated in advanced gastric cancer compared with early-stage gastric cancer. PTEN expression in gastric cancer showed a negative association with lymph node metastasis (t= 3.91, P<0.01), invasion depth (t= 1.95, P<0.05) and age (t= 4.69, P<0.01). MVD in PTEN-negative gastric cancer was significantly higher than that in PTEN-positive gastric cancer (t=3.69, P<0.01), and there was a negative correlation betweenPTEN expression and MVD (γ=-0.363, P<0.05). VEGF expression was positively associated with invasion depth (especially with serosa invasion, t = 4.69, P<0.01), lymph node metastasis (t= 2.31, P<0.05) and TNM stage (t= 3.04, P<0.01). MVD in VEGF-positive gaslyic cancer was significantly higher than that in VEGF-negative gastric cancer (t=4.62, P<0.01), and there was a positive correlation between VEGF expression of and MVD (y = 0.512, P<0.05). VEGF expression in PTEN-negative gaslyic cancer was significantly stronger than that in PTEN-positive gastric cancer (t=2.61, P<0.05), and there was a significantly negative correlation between the expression of VEGF and PTEN (γ=-0.403, P<0.05).CONCLUSION: Our results imply that inactivation of PTEN gene and over-expression of VEGF contribute to the neovascularization and progression of gastric cancer. PTEN-related angiogenesis might be attributed to its up-regulation of VEGF expression. PTEN and VEGF could be used as the markers reflecting the biologic behaviors of tumor and viable targets in therapeutic approaches to inhibit angiogenesis of gastric cancers.

Mechanism of 5-fluorouracil required resistance in human hepatocellular carcinoma cell line Bel_(7402)

AIM:To investigate the resistance mechanism of 5-fluorouracil(5-FU)in Bel7402/5-FU cells which was established in our lab by in vitro continuous stepwise exposure of human hepatocellular carnoma(HCC) cell line Bel7402 to 5-FU.

Adaptive cytoprotection through modulation of nitric oxide in ethanol-evoked gastritis

AIM: To assess the mechanisms of protective action by different mild irritants through maintenance of gastric mucosal integrity and modulation of mucosal nitric oxide (NO) in experimental gastritis rats.METHODS: Etcher 200 mL/L ethanol, 50 g/L NaG or 0.3 mol/L HCl was pretreated to normal or 800 mL/L ethanol-induced acute gastritis Sprague-Dawley rats before a subsequent challenge with 500 mL/L ethanol. Both macroscopic lesion areas and histological damage scores were determined in the gastric mucosa of each group of animals. Besides,gastric mucosal activities of NO synthase isoforms and of superoxide dismutase, along with mucosal level of leukotriene (LT)C4 were measured.RESULTS: Macroscopic mucosal damages were protected by 200 mL/L ethanol and 50 g/L NaCI in gastritis rats.However, although 200 mL/L ethanol could protect the surface layers of mucosal cells in normal animals (protection attenuated by NG-nitro-L-arginine methyl ester), no cytoprotection against deeper histological damages was found in gastritis rats. Besides, inducible NO synthase activity was increased in the mucosa of gastritis animals and unaltered by mild irritants. Nevertheless, the elevation in mucosal LTC4 level following 500 mL/L ethanol administration and under gastritis condition was significantly reduced by pretreatment of all three mild irritants in both normal and gastritis animals.CONCLUSION: These findings suggest that the aggravated 500 mL/L ethanol-evoked mucosal damages under gastritis condition could be due to increased inducible NO and LTC4 production in the gastric mucosa. Only 200 mL/L ethanol is truly 'cytoprotective' at the surface glandular level of nongastritis mucosa. Furthermore, the macroscopic protection of the three mild irritants involves reduction of LTC4 level in both normal and gastritis mucosa, implicating preservation of the vasculature.

Stem cell pluripotency and transcription factor Oct4

Mammalian cell totipotency is a subject that has fascinated scientists for generations. A long lasting question whether some of the somatic cells retains totipotency was answered by the cloning of Dolly at the end of the 20th century. The dawn of the 21st has brought forward great expectations in harnessing the power of totipotentcy in medicine. Through stem cell biology, it is possible to generate any parts of the human body by stem cell engineering. Considerable resources will be devoted to harness the untapped potentials of stem cells in the foreseeable future which may transform medicine as we know today. At the molecular level, totipotency has been linked to a singular transcription factor and its expression appears to define whether a cell should be totipotent. Named Oct4, it can activate or repress the expression of various genes. Curiously, very little is known about Oct4 beyond its ability to regulate gene expression. The mechanism by which Oct4 specifies totipotency remains entirely unresolved. In this review, we summarize the structure and function of Oct4 and address issues related to Oct4 function in maintaining totipotency or pluripotency of embryonic stem cells.

Effects of Matrine on Aconitine-Induced Electrophysiological Changes in Rat Ventricular Myocytes

Aim To explore the reason that the antiarrhythmic effect of the extract oftraditional Chinese medicinal herb, matrine, is weaker than quinidine and verapamil by comparison ofthe effect and efficacy of matrine on various kinds of transmembrane ionic currents with those ofquinidine and verapamil; and to demonstrate the best targets for antiarrhythmic drugs. MethodsWhole-cell patch-clamp techniques were used to record the action potential and ionic currents insingle cells of rat ventricular myocytes. Aconitine was used to induce the changes of ioniccurrents, then study the effects of matrine and quinidine, verapamil on aconitine-induced unbalancedchannel currents and action potential. Results Aconitine 1 μmol·L^(-1) induced significantchanges in transmembrane currents and action potential in single cells of rat ventricular myocytes.APD was significantly prolonged by aconitine. Simultaneously, aconitine increased sodium, L-typecalcium and inward rectifier potassium currents. Matrine 100 μmol· L^(-1) reversed theaconitine-induced changes of sodium current (I_(Na)) from (-70.2+- 10.5) pA/pF to ( - 39.6+-4.0)pA/pF(n = 5, P < 0.05 vs aconitine); L-type calcium current (I_(Ca-L)) from (20.4+- 3.8) pA/pF to (- 12.9+- 2.9) pA/pF ( n = 6, P < 0.01); the inward rectifier potassium current (I_(k1) ) from (-32.2+- 1.08) pA/pF to ( -24.0+-3.4) pA/pF (n = 6, P < 0.01), and action potential duration. Thereversal effects of quinidine and verapamil on aconitine-induced changes of APD and ionic currentswere more marked than matrine. Conclusion Aco-nitine significantly disturbs the normal equilibriumof ion channels in ventricular myocytes. It induces changes of I_(Na), I_(Ca-L), I_(K1) andprolongation of action potential duration. Matrine at concentration 50 or 100 μmol·L^(-1)statistically significantly suppresses aconitine-induced changes of APD and ionic currents. Thepotency and efficacy of inhibitory effect of matrine are markedly weaker than those of commonly usedverapamil and quinidine.

Helicobacter pyloripromote gastric cancer cells invasion through a NF-κB and COX-2-mediated pathway

AIM: To examine the effects of Helicobacter pylori(Hpylori) infection on the invasiveness of gastric cancer cells,and to elucidate its mechanism. METHODS: Gastric carcinoma cells, MKN-45, were incubated with CagA-positive H pylori, and cell invasion was determined by Matrigel analysis.The expression of matrix metallopr-oteinase-9 (MMP-9),vascular endothelial growth factor (VEGF), and cyclooxygenase-2 (COX-2) were assessed by Western-blot analysis, and transcriptional activation of the COX-2 promoter was examined by measuring luciferase and β-galactosidase activities. Lastly,the proteinDNA interaction was confirmed by an electrophoretic mobility shift assay. RESULTS: The current studies showed that: (1) incubation of CagA-positive H pylori with MKN-45 cells significantly promotes gastric cancer cells invasion, and this effect is attenuated by pre-treatment with NS-398, a COX-2 inhibitor, or PDTC,a nuclear factor κB (NF-κB) inhibitor;(2) the induction of MKN-45 cells invasion by Hpylori is associated with increases in COX-2, MMP-9, and VEGF protein expression, and co-incubation of NS-398 or PDTC significantly reduces these effects;(3) H pylori infection transactivates COX-2 promoter activity and increases the binding of NF-κB to this promoter. CONCLUSION: Our data demonstrate that H pylori infection promotes gastric epithelial cells invasion by activating MMP-9 and VEGF expression. These effects appear to be mediated through a NF-κB and COX-2 mediated pathway, as COX-2 or NF-κB inhibitor significantly attenuate the invasiveness of gastric cancer cells and the expressions of MMP-9 and VEGF protein.

Protective effects of Rheum tanguticum polysaccharide against hydrogen peroxide-induced intestinal epithelial cell injury

AIM: To describe the effect of Rheum tanguticum polysaccharide (RTP) on hydrogen peroxide-induced human intestinal epithelial cell injury. METHODS: Hydrogen peroxide (100 μmol/L) was introduced to induce human intestinal epithelial cell injury. Cells were pretreated with RTP (30,100,300 μg/mL) for 24 h before exposure to hydrogen peroxide. Cell viability was detected by MTT assay and morphological observation. Acridine orange staining and flow cytometry were performed to assess cell apoptosis. Lactate dehydrogenase (LDH) activity, production of malondialdehyde (MDA) and superoxide dismutase (SOD) activity were measured by spectrophotometry with corresponding assay kits. RESULTS: Following exposure to H2O2, a marked decrease in cell survival and SOD activity, increased production of MDA, LDH leakage and cell apoptosis were found. Pretreatment of the cells with RTP could significantly elevate cell survival, SOD activity and decrease the level of MDA, LDH activity and cell apoptosis. CONCLUSION: RTP may have cytoprotective and anti-oxidant effects against H2O2-induced intestinal epithelial cell injury by inhibiting cell apoptosis and necrosis. This might be one of the possible mechanisms of RTP for the treatment of ulcerative colitis in rats.

Clinical study on nutrition support in patients with severe acute pancreatitis

AIM: To investigate the effect of nutritional support therapy on severe acute pancreatitis (SAP).METHODS: A total of 96 patients with severe acute pancreatitis were divided randomly into control and treatment groups.The former group received total parenteral nutrition (TPN)via central venous infusion, while parenteral nutrition (PN)and enteral nutrition (EN) therapies were applied in different phases for the latter group. The nutrition status, acute phase responses, pancreas lesions, enteric mucosa penetrability and immune functions were monitored.RESULTS: Body weight and prealbumin concentration were increased in treatment group, compared to those in the control group, but albumin concentration did not change significantly.Acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ)scores decreased after 7 d of treatment, whereas the scores of the control group decreased on the 11th day. Concentrations of tumor necrosis factor-α (TNF-α), interleukine-6 (IL-6) and serum C reactive protein (CRP) dropped earlier in the treatment group (on the 4th day) than that in the control group (on the 7th day). No difference was observed in pancreatic lesions between the control and treatment groups.Concentration of endotoxin and lactulose/manicol (L:M) ratio of urine did not change in treatment group, but those in the control group were elevated markedly. Compared with the treatment group, CD4:CD8 T cells ratio and immunoglobulin G (IgG) concentration in the control group decreased significantly.CONCLUSION: Compared to TPN, the combined therapy of EN and PN could improve the nutrition status and moderate the acute phase response obviously. Moreover, the integrity of enteric mucosa and immune function were protected more effectively in treatment group than in the control one. On the other hand, EN did not simulate the excretion of pancreas and avoid exaggerating the inflammation of pancreas. Thus,appropriate application of PN and EN appears to be more effective for patients with SAP.

PROTECTIVE EFFECT OF TETRAMETHYLPYRAZINE ON LEARNING AND MEMORY FUNCTION IN D-GALACTOSE-LESIONED MICE

To explore the protective effect of tetramethylpyrazine (TMP) on the learning and memory function in D-galactose (D-gal)-lesioned mice. Methods C57BL/6 mice were injected (s.c.) 2% D-gal for 40 days (100 mg·kg-1·d-1). Normal saline, TMP, and Huper-zine A were respectively given by intragastric administration in different groups from the third week. Learning and memory ability was tested with Morris water maze for 5 days at the sixth week. After completion of behavioral test, the mice were sacrificed by decapitation. The brain was rapidly removed, and the cortex and hippocampus were separated. The superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in the cortex were determined. At the same time, the activity of choline acetyltransferase (ChAT) and acetylcholinesterase (AChE), the binding sites (Bmax) and the affinity (KD) of M-cholinergic receptor in the cortex, and Bmax and KD of N-methyl-D-aspartate (NMDA) receptor in the hippocampus were determined. Results In this model group, (1) The deficit of learning and memory ability, (2) elevated MDA content and lowered SOD activity, (3) decreased AChE activity and M-cholinergic receptor binding sites in the cortex, and (4) lowered NMDA receptor binding sites were observed in the hippocampus, as compared with the normal control. TMP could markedly (1) attenuate cognitive dysfunction, (2) lower MDA content and elevate SOD activity, (3) increase the activity of ChAT and AChE, and M-cholinergic receptor binding sites in the cortex in the mice treated with D-gal. NMDA receptor binding sites were also increased in the hippocampus in the treated mice. Conclusion TMP can significantly strengthen antioxidative function, improve central cholinergic system function, protect NMDA receptor activity, and thus enhance the learning and memory ability in D-gal-lesioned mice.

Effect of rat serum containing Biejiajian oral liquid on proliferation of rat hepatic stellate cells

AIM: Liver fibrosis is a common pathological process of chronic liver diseases. Activation of hepatic stellate cells(HSCs) is the key issue in the occurrence of liver fibrosis. In this study, we observed the inhibitory action of rat serum containing Biejiajian oral liquid (BOL), a decoction of turtle shell, on proliferation of rat HSCs, and to explore the antihepatofibrotic mechanisms of BOL.METHODS: A rat model of hepatic fibrosis was induced by subcutaneous injection of CC14. Serum containing low,medium and high dosages of BOL was prepared respectively.Normal and fibrotic HSCs were isolated and cultured. The effect of sera containing BOL on proliferation of HSCs was determined by 3H-TdR incorporation.RESULTS: The inhibitory rate of normal rat HSC proliferation caused by 100 mL/mL sera containing medium and high dosages of BOL showed a remarkable difference as compared with that caused by colchicine (medium dosage group:34.56±4.21% vs29.12±2.85%, P<0.01; high dosage group:37.82±1.32% vs29.12±2.85%, P<0.01). The inhibitory rate of fibrotic rat HSC proliferation caused by 100 mL/L serum containing medium and high dosages of BOL showed a remarkable difference as compared with that caused by colchicine (medium dosage group: 51.31_+3.14% vs 38.32_+2.65%,P<0.01; high dosage group: 60.15_+5.36% vs38.32_+2.65%,P<0.01). The inhibitory rate of normal rat HSC proliferation caused by 100 mL/L and 200 mL/L sera containing a medium dosage of BOL showed a significant difference as compared with that caused by 50 mL/L (100 mL/L group: 69.02±9.96%vs 50.82±9.28%, P<0.05; 200 mL/L group: 81.78±8.92%vs50.82±9.28%, P<0.01). The inhibitory rate of fibrotic rat HSC proliferation caused by 100 mL/L and 200 mL/L sera containing a medium dosage of BOL showed a significant difference as compared with that caused by 50 mL/L (100 mL/L group:72.19±10.96% vs 61.38±7.16%, P<0.05; 200 mL/L group:87.16±8.54% vs 61.38±7.16%, P<0.01).CONCLUSION: Rat serum containing BOL can inhibit proliferation of rat HSCs, and the inhibition depends on the dosage and concentration of BOL. The inhibitory effect on HSC proliferation is one of the main anti-hepatofibroticmechanisms of BOL.

Inhibition of β-ionone on SGC-7901 cell proliferation and upregulation of metalloproteinases-1 and -2 expression

AIM:To observe the effect of β-ionone on the proliferation of human gastric adenocarcinoma cell line SGC-7901 and the inhibition of metalloproteinase.METHODS:Using growth inhibition, Zymograms assays and reverse transcription-polymerase-chain reaction (RT-PCR),we examined cell growth rates,activities of matrix metalloproteinases-2 (MMP-2) and-9 (MMP-9),and expression of metalloproteinases-1 (TIMP-1) and-2 (TIMP-2) in SGC-7901 cells after the treatment with β-ionone for 24 h and 48h, respectively.RESULTS:β-ionone had an inhibitory effect on the growth of SGC-7901 cells.Eight days after the treatment with β-ionone at concentrations of 25, 50, 100 and 200μmol/L,the inhibition rates were 25.9%, 28.2%, 74.4% and 90.1%,respectively. The IC50 value of β-ionone for SGC-7901 cells was estimated to be 89μmol/L.The effects of β-ionone on MMP-2 and MMP-9 activities in SGC-7901 cells were not observed. However,the levels of TIMP-1 and TIMP-2 transcripts were elevated in cells treated with β-ionone in a dose-dependent manner.CONCLUSION:β-ionone can inhibit the proliferation of SGC-7901 cells,upregulate the expression of TIMP-1 and TIMP-2 expression, and may influence metastasis of cancer.

Expression and activities of three inducible enzymes in the healing of gastric ulcers in rats

AIM: To explore the roles of nitric oxide synthase (NOS),heme oxygenase (HO) and cyclooxygenase (COX) in gastric ulceration and to investigate the relationships of the expression and activities of these enzymes at different stages of gastric ulceration.METHODS: Gastric ulcers (kissing ulcers) were induced by luminal application of acetic acid. Gastric tissue samples were obtained from the ulcer base, ulcer margin, and nonulcerated area around the ulcer margin at different time intervals after ulcer induction. The mRNA expression and protein levels of inducible and constitutive isoforms of NOS,HO and COX were analyzed with RT-PCR and Western blotting methods. The activities of the total NOS, inducible NOS (iNOS), HO, and COX were also determined.RESULTS: Differential expression of inducible iNOS, HO-1and COX-2 and enzyme activities of NOS, HO and COX were found in the gastric ulcer base. High iNOS expression and activity were observed on day 1 to day 3 in severely inflamed ulcer tissues. Maximum expressions of HO-1 and COX-2 and enzyme activities of HO and COX lagged behind that of iNOS,and remained at high levels during the healing phase.CONCLUSION: The expression and activities of inducible NOS, HO-1 and COX-2 are found to be correlated to different stages of gastric ulceration. Inducible NOS may contribute to ulcer formation while HO-1 and COX-2 may promote ulcer healing.

Experimental study of anti-tumor effects of polysaccharides from Angelica sinensis

AIM: To investigate the in vivo anti-tumor effects of total polysaccharide (AP-0) isolated from Angelica sinensis (Oliv.)Diels (Danggui) on mice and thein vitro inhibitory effects of AP-0 and its sub-constituents (AP-1, AP-2 and AP-3) on invasion and metastasis of human hepatocellular carcinoma.METHODS: Three kinds of murine tumor models in vivo,sarcoma 180 (S180), leukemia L1210 and Ehrlich ascitic cancer (FAC) were employed to investigate the anti-tumor effects of AP-0. For each kind of tumor model, three experimental groups were respectively given AP-0 at doses of 30, 100 and 300 mg/kg byip once a day for 10 days.Positive control groups were respectively given Cy at a dose of 30 mg/kg for S180 and leukemia L1210, and 5-FU at a dose of 20 mg/kg for EAC. On d 11, mice bearing S180were sacrificed and the masses of tumors, spleens and thymus were weighed. The average living days of mice bearing EAC and of mice bearing L1210 were observed,and the rates of life prolongation of each treatment were calculated, respectively. The inhibitory effects of APs on hepatoma invasion and metastasis in vitro were investigated by employing human hepatocellular carcinoma cell line (HHCC) with the Matrigel invasion chamber, adhesion to extracelluler matrix and chemotatic migration tests, respectively.RESULTS: AP-0 had no obviously inhibitory effect on the growth of S180, but it could significantly decrease the thymus weights of the mice bearing S180. AP-0 could significantly reduce the production of ascitic liquids and prolong the life of mice bearing EAC. AP-0 could also increase the survival time of mice bearing L1210. AP-0 and AP-2 had significantly inhibitory effects on the invasion of HHCC into the Matrigel reconstituted basement membrane with the inhibitory rates of 56.4% and 68.3%, respectively. AP-0, AP-1, AP-2 and AP-3 could influence the adhesion of HHCC to extracellular matrix proteins (Matrigel and fibronectin) at different degrees, among them only AP-3 had significant blocking effect on the adhesion of HHCC to fibronectin with an inhibitory rate of 30.3%. AP-0, AP-1 and AP-3 could partially inhibit the chemotactic migration abilities of HHCC.CONCLUSION: The experimental findings suggest that total polysaccharide of Angelica sinensis (Oliv.) Diels (Chinese Danggui) possesses anti-tumor effects on experimental tumor models in vivo and inhibitory effects on invasion and metastasis of hepatocellular carcinoma cells in vitro.